Poor Heat Detection in Cows Costs Dairies Money

It results in excessive days not pregnant and long calving intervals.

The major factor limiting optimum reproductive performance on many dairy farms is failure to detect cows in heat in a timely and accurate manner. Poor heat detection results in an excessive number of days not pregnant or days open, which causes long calving intervals, explains Michael L. O’Connor, Professor of Dairy Science at Pennsylvania State University.

This is economically important to the dairy business, because for every day a cow is not pregnant beyond 120 days after calving it can cost about $2 per cow per day, says O’Connor, whose specialty is dairy reproductive management. For a 250-cow herd with an average of 140 days open, the cost could be $40 additional per cow — a $10,000 herd total per year— more than the same herd with an average 120 days open.

Several systems are available to help dairy producers improve their heat detection rate or the number of cows submitted for breeding at the proper number of days after calving. Estrous synchronization programs are designed to cause cows to come into heat over a short period of time so they can be inseminated in a timely manner, according to O’Connor. Heat detection is required for
these programs.

Potential Benefits

O’Connor cites these potential benefits of well managed estrus-synchronization programs:

• Improved efficiency of heat detection
• More timely first service
• Improved pregnancy rate, resulting in a reduction in the variation in calving intervals among cows
• Potentially reduced involuntary culling forreproductive reasons
• Labor for reproductive management concentrated to specific time periods
• Improved overall reproductive performance of the herd

Achieving Success

The following factors are important for achieving success with synchronization programs, according to O’Connor:

• A high percentage of the cows must be cyclingnormally. Nutritional, environmental or diseasefactors that prevent cows from cycling (anestrus) or cause low conception must be corrected before starting a synchronization program.
• Although certain synchronization programs will induce some anestrous cows to ovulate, pregnancy rates will significantly increase in relation to the percentage of cows that are cycling at the onset of the program.
• Pregnancy rates are significantly higher for cows with Body Condition Scores (BCS) greater than 2.5 compared to cows with BCS less than 2.5.
• Herd managers and employees must make a commitment to the estrous synchronization program.
• Accurate records must be kept. A list of eligible cows must be updated regularly. A calendar or electronic record system should be used so injections, heat detection and inseminations are performed on the correct days specified for the system. Appropriate personnel should be available to perform these tasks correctly. Standard operating procedures (SOP) should be posted and understood by everyone.
• Efficient and accurate heat detection for the specified days is essential when using the synchronization programs that require heat detection. Heat detection must be intensified on the days when cows are likely to exhibit heat. Use of heat detection aids is recommended.
• To maximize the effectiveness of any system, postbreeding heat detection (detection or return heats) must be high.
• Herd managers and employees must adhere to the time schedule for injections, heat detection, insemination and pregnancy examinations.
• The proper amount of hormone must be given in the correct location.
• Use the correct size syringe when administering hormone doses. Review procedures with your
  veterinarian. Store hormones according to label directions, including refrigeration where indicated.
• Pregnancy examinations must be scheduled routinely so non-pregnant cows are identified
  and scheduled back into the synchronization program.
• Pregnancy rates are higher when the timed insemination occurs shortly after day 75 postpartum than before day 75.

Successful reproductive management depends upon team work, concludes O’Connor. “Herd managers should consult with the veterinarian, artificial insemination personnel and employees so everyone is working toward the same objective.”

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